Wednesday, March 20, 2013

Rethinking the Role of Antioxidants

I always feel virtuous in the morning when I have plain Greek yogurt topped with blueberries. “What a cancer-fighting start to the day!” I think to myself.

Blueberries, as you probably know, are very high in compounds called “antioxidants.” You can find a WebMD write-up about them here. They, and other foods like apples, broccoli and eggplant, are thought to neutralize rogue oxygen molecules that can damage DNA. If you can prevent these “free radicals” from ripping apart cell components like DNA, the thinking goes, you may be able to block the genetic mutations that lead to cancer.

Alas, a world-renowned cancer researcher now says it may not be that simple. In fact, he suggests that taking antioxidants may actually be harmful for some cancer patients. They may actually prevent chemo drugs and radiation from killing cancer cells.

I was on a family vacation the first week of January and completely missed this when it first came out January 8: James Watson—the co-discoverer of DNA, Nobel laureate and director emeritus of the Cold Spring Harbor Laboratory, a prestigious cancer research center—took on the cancer research establishment in an essay in Open Biology.

Watson, who won his Nobel for detailing the structure of DNA with his partner Francis Crick and who has focused primarily on cancer research since 1994, made many points in his essay: He says that our current approach to cancer research is not likely to find a cure.

Recently, the great hope in cancer research has been that we would find specific genes that, when garbled, cause cancer. Then, the thinking went, we’d find drugs that would repair or block that garbled DNA, thus stopping the runaway cell division that we call cancer. Yet so far, none of the new therapies, Watson points out, cure cancer. They may work for a few months, but they’re completely powerless against metastatic cancers.

Here’s why: If you block one pathway that certain cancer cells use to multiply, they’ll find a work-around. And remember, there are hundreds, if not thousands, of kinds of cancer. So Watson is suggesting that rather than zeroing in on gene mutations specific to certain cancers, we should look for things that are common to all cancer cells, things like free radicals.

If you have lots and lots of free radicals in a cell, the cell goes into “auto-destruct mode.” The cell dies, and is replaced by a new cell. Your body replaces a million cells a second. That’s pretty cool, right?

Lots of cancer therapies, many chemo drugs and radiation therapy, work by increasing the number of free radicals in cancer cells, interfering with cellular processes until the auto-destruct order goes out. That’s why, Watson argues in an essay this week in New Scientist and in a lecture posted on-line this week by UCLA, taking antioxidants may actually be harmful for cancer patients. He proposes that drugs that block antioxidants—you could call them anti-antioxidants—might make existing cancer drugs more effective.

As you might imagine, Watson’s arguments created quite a kerfuffle in the cancer world. After all, cancer researchers are unlikely to change course on a dime and “cancer-fighting” antioxidants—selenium, beta-carotene, vitamins A, C and E—are added to everything from energy drinks to breakfast cereal to …you name it.

While few scholars are likely to openly disrespect a scientific legend like Watson, some did point out that his article is an “opinion piece,” that is, a suggestive proposal rather than an assertion backed by hard evidence.

Still, it’s opinion from one of the leading scientists of our time. And is it that difficult to imagine that we the public have been oversold on the cancer-fighting properties of antioxidants? Watson isn’t saying that antioxidants cause cancer, as many popular press sites reported. He’s saying that’s it complicated, and that it’s especially complicated for cancer patients.

I think that Watson’s essays serve as a reminder: It’s always good to remember that things are never as simple as we would think or want. Remember “junk DNA,” bits of genetic code that didn’t seem to mean anything? It turns out that it actually has a purpose.

Things are always part of a complex system, often a system that we don’t fully understand. So it’s unlikely that one component of your diet—whether it’s fat, carbs or sugar or high-fructose corn syrup—is the source of all ills. It’s equally unlikely that one supplement, whether antioxidants or shark cartilage or whatever, is going to save the world from cancer.

As cancer patients, we need to cultivate two seemingly contradictory habits of mind: We need to keep our minds open. Neither we, nor our doctors, know everything about cancer. We also need to nurture a healthy skepticism. Easy answers aren’t really out there.

I’ll be interested to see if Watson’s ideas gain traction. After all, they are the result of decades of cancer research experience. In the meantime, since I’m not in active cancer treatment, I’m still eating blueberries and yogurt in the morning. What about you?

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Heather Millar

Heather Millar is an award-winning freelance writer and author. In her blog My Left Breast, she details her treatment for breast cancer as well as the science, history, and ethics of the disease.